HBW 8 - Black-spotted Bare-eye (Phlegopsis nigromaculata)

207. Black-spotted Bare-eyePhlegopsis nigromaculata

Taxonomy. Myothera nigro-maculata d'Orbigny and Lafresnaye, 1837, Plains of Guarayos, Santa Cruz, Bolivia.
May prove to be a member of an obligate ant-following clade. Occasionally interbreeds with P. erythroptera; form described as P. barringeri ("Argus Bare-eye") shown to be a hybrid between the two. S populations (Rondônia and Mato Grosso S to NE Bolivia) tentatively included in race bowmani, but may represent an undescribed race; taxonomic study needed. Four subspecies recognized.

Descriptive notes. 16·5-17·5 cm; 42-51 g. Bare periorbital patch red. Nominate race has head and neck down to centre of belly black; upperparts and wing-coverts light olive, covered with large, oval-shaped (longer than wide) black spots edged pale yellowish olive-brown; flight-feathers cinnamon-rufous, tertials with large black spots; tail rufous-chestnut; lower underparts olive-brown, becoming cinnamon-rufous posteriorly; underwing-coverts mixed olive-brown and black. Female is like male. Races vary mainly in colour of upperparts and size and shape of spots: confinis resembles nominate but smaller, more heavily spotted, bare facial patch more extensive; bowmani has upperparts brighter, more yellowish, spots wider than long (larger and triangular in W of range); paraensis is light rufous-brown above, spots small and rounded with cinnamon edges, larger bare facial patch. VOICE. Loudsong a short series (e.g. 3 notes, 2·6 seconds) of moderately long, flat, rich whistles, each slightly lower in pitch and becoming harsher in quality, final note typically drops in intensity, number of notes variable. Calls include abrupt "chip", a long (e.g. 0·7 seconds) "chirr" falling in pitch and intensity, and a short series (e.g. 4 notes) of lengthening notes that drop in pitch.Habitat. Understorey of humid lowland and foothill evergreen forest, mostly below 600 m, locally to 900 m. In W of range found primarily in floodplain-forest (várzea, transitional), and replaced in many areas of upland forest by P. erythroptera; in Brazil E of R Madeira, occurs in terra firme, transitional forest and várzea and igapó floodplain-forest. In all parts of range, may follow army ants into adjacent tall second-growth woodland.Food and Feeding. Feeds on variety of insects and other arthropods, also on small reptiles; virtually all food obtained when flushed by swarms of army ants. Recorded prey in Brazil include grasshoppers (Acrididae), crickets (Gryllidae), katydids (Tettigoniidae), cockroaches (Blattidae), hemipterans, beetles (Coleoptera), termites (Isoptera), ant larvae (Formicidae), spiders and their egg sacs, scorpions (Scorpiones), centipedes (Chilopoda), and small lizards. Pair-members, individuals, or family groups forage mostly below 1 m (c. 75%), but subordinate individuals often displaced to higher perches, occasionally to 5 m, seldom higher; multiple pairs and family groups (up to 22 individuals) may simultaneously attend a single ant swarm; does not associate with mixed-species flocks, but often forages in presence of other species at ant swarms. Considered an obligate army-ant follower, rarely seen away from ants; once recorded as remaining near domestic pigs at forest edge, presumably to obtain prey flushed by the mammals. Wanders widely in search of ants early in morning, frequently first checking raiding paths and bivouac sites from previous day; if not successful, wanders more widely, immediately investigating vocalizations of both conspecifics and other obligate ant-followers; once a nomadic swarm is located, birds stay with it for most or all of the day, sometimes leaving to monitor nearby statary swarms. Progresses by heavy hops and short, fluttery flights. Selects mostly slender perches 1-4 cm in diameter, using horizontal and diagonal perches about as often as vertical ones, but more adept at using latter than is its larger congener P. erythroptera. Most attack manoeuvres are sallies or sally-pounces of less than 0·5 m from perch to ground, where prey seized by a quick stab of the bill, or after a short lunge or series of rapid bounding hops after more mobile prey, before returning to a perch; less frequently, makes short aerial sallies, or sallies to foliage, trunks, branches, vines or other surfaces, or perch-gleans by reaching up, out or down; occasionally hops on ground between columns of ants and flips leaf litter with its bill to uncover hidden prey, but this behaviour less frequent than in P. erythroptera. Dominant over most other ant-following antbirds, including Pyriglena leuconota, but subordinate to Skutchia borbae and P. erythroptera where co-occurring with these. As with most other dominant ant-followers, submissive behaviour and family sociality are better developed than in subordinate species, probably facilitating shared foraging opportunities by multiple pairs or families over same swarm; agonistic behaviour towards conspecifics nevertheless frequent.Breeding. Nest found in Jul in Colombia; breeds in Aug-Mar in Brazil and Oct-Feb in Peru; in Ecuador nest found in Apr, and gonadal condition of females and presence of fledglings or juveniles indicate season Oct-Jun, and possibly throughout year (based on gonadal condition of males). Recent observation of apparent "helper" at nest attended by 3 adults (female, 2 males) in Peru (Cocha Cashu). Nest in Colombia an open cup constructed of dry bamboo leaves, lined with small plant fibres, placed 1 m above ground inside hollow 10 cm deep in rotten stump, partially covered by leaves of an epiphytic aroid; in Ecuador a bowl-shaped mat of palm leaflets and thin vines placed in stump of stilt-root palm (Iriartea deltoidea) that had rotted such that its centre formed cup-like cavity with opening on one side; in Peru, one nest was composed of a few small pieces of brown palm frond, making a loose flat lining inside low vertical cavity (internal depth 10 cm, diameter 7·7 × 7·3 cm) of live tree 8 cm above ground, four others also loosely lined flat structure, in two cases of thin strips of brown palm fronds, and placed 0·3-0·5 m up in hollow of dead stump. Normal clutch 2 eggs, pale pink with dense, wavy mauve lines (Ecuador), or vinaceous with heavy purple streaks and spots (Colombia); incubation by both parents, usually by male in morning and probably again in late afternoon, by female in middle of day and again through night, incubation period not recorded; both also share in brooding and feeding of chicks, nestling period at least 13 days; within 1 month of first days of incubation stub-tailed fledglings appear at army-ant swarms, where fed by parents, and within a further month are capturing some of their own food; young remain with parents at ant swarms for at least 3-5 months. Nest success thought to be higher than for most small forest birds; of 3 nests in a study in Peru, 2 successfully fledged both young, third was preyed on at egg stage. In Amazonian Brazil low annual adult mortality (estimated at 15%), perhaps due to dominance at ant swarms over other ant-following species, resulting in reduced interspecific competition and starvation.Movements. None recorded; presumed resident.Status and Conservation. Not globally threatened. Uncommon to fairly common throughout most of its extensive range. Occurs in several formally protected large areas, e.g. Amacayacu National Park, in Colombia, Manu National Park/Biosphere Reserve and Tambopata-Candamo Reserved Zone, in Peru, Pacaás-Novos and Tapajós National Parks, Rio Cristalino State Park and Caxiuanã Forest Reserve, in Brazil, and Madidi and Noel Kempff Mercado National Parks, in Bolivia. Also present in several privately protected reserves centred around ecotourist lodges or camps, e.g. Cuyabeno and Imuyacocha, in Ecuador, and Explorama, Explornapo and ACEER lodges, in Peru. In addition, range encompasses extensive areas of intact habitat which, although not formally protected, seem to be at little of development in near future. Considered to be of medium sensitivity to human disturbance.Bibliography. Allen (1995), Alverson et al. (2001), Bates et al. (1989), Brace et al. (1997), Butler (1979), Cadena, Londoño & Parra (2000), Chesser (1995), Clements & Shany (2001), Cory & Hellmayr (1924), Dubs (1992), Foster et al. (1994), Francis et al. (1999), Graves (1992), Haffer (1992, 1997), Hill & Greeney (2000), Hilty & Brown (1986), Isler & Whitney (2002), Killeen & Schulenberg (1998), Naumburg (1939), Novaes (1970, 1973, 1974, 1976), O'Neill & Pearson (1974), Oniki (1972), Oniki & Willis (1983), Oren & Parker (1997), Parker & Bailey (1991), Parker et al. (1982), Pearson (1975c, 1977b), Remsen & Traylor (1989), Remsen et al. (1986), Ridgely & Greenfield (2001), Ridgely & Tudor (1994), Ridgely et al. (1998), Robinson & Terborgh (1997), Rodner et al. (2000), Ruschi (1979), Schubart et al. (1965), Servat (1996), Sick (1993), da Silva (1996), da Silva et al. (1990), Stotz, Fitzpatrick et al. (1996), Stotz, Lanyon et al. (1997), Tallman, D.A. & Tallman (1997), Tallman, E.J. & Tallman (1994), Taylor (1995), Terborgh, Fitzpatrick & Emmons (1984), Terborgh, Robinson et al. (1990), Willis (1979a, 1979c), Willis & Oniki (1978), Willson-Hillman (2003), Zimmer, J.T. (1932e), Zimmer, K.J. (2003a), Zimmer, K.J., Parker et al. (1997).